In the electronics industry, large numbers of components known as hybrids are used. The typical hybrid comprises a substrate on which a circuit is printed and various components such as microcircuit chips are connected to the printed circuit by very fine wires. Discrete components such as capacitors, resistors and the like may also be mounted on the substrate. The hybrid is very small and very careful inspection techniques are necessary to ensure consistent quality.
Conventional inspection techniques, such as viewing the hybrid through a magnifier and comparing it with a diagram or photograph, can be very time consuming and tiring to the eyes. Automatic circuit testing equipment can indicate faults, but visual inspection is still required to identify the fault and correct the component.
The optical comparator disclosed in the above mentioned copending application provides magnified mirror images of a master component and a production component in confronting relation, so that the comparable circuit elements can be directly compared. Access is provided to the production component while in the viewing position, so that a probe can be inserted to mark or correct inconsistencies and the work observed on the image. Each image is visible to one eye, the images being combined by the normal stereoscopic action of the eyes. If both eyes do not have equal vision, optical compensation can be provided, but must be adjusted for each individual.